1) [-55; 7]
2) [(-2)4(-2) = -16]
3) [|A| = -p^2 - 5p + 6, sing. pro p=1, -6, reg. pro p ruzna od nich; |A| = p^2 + 6p - 7, sing. pro p=1,-7, reg. pro p ruzna od 1 a -7]
4) [(p-1)(p+4)]
5) [
     0   1/3  1/3
     1   -1    0
     1  -1/3 -1/3
    ]
6) [
     1  -1  0
    -1   1  1
    -1   0  2
]

7) [
   (-a^2+3a-1)/(a-1)(a+6)   (1+a)/(a+6)    (2a-3)/(a-1)(a+6)
         (a-5)/(a+6)           -1/(a+6)     (3+a)/(a-1)(a+6)
       (-2a-1)/(a-1)(a+6)       1/(a+6)         3/(a-1)(a+6)
]